Characteristics, sources, and transport of tetrabromobisphenol A and bisphenol A in soils from a typical e-waste recycling area in South China

We studied the tetrabromobisphenol A (TBBPA) and bisphenol A (BPA) patterns and their sources and transport in different land-use soils from Longtang, South China, a typical electronic waste recycling center. We also studied the reductive debromination of TBBPA in paddy soils. TBBPA and BPA concentrations (on a dry weight basis) were undetected-220 and 0.50-325 ng/g, respectively, and both increased, by similar factors, in the following order: pond sediments < paddy soils = vegetable soils < wasteland < dismantling sites < former open burning sites. BPA concentrations were higher than TBBPA concentrations in all six land-use soils, and they correlated significantly. TBBPA and BPA were transported through the soil profiles, being found at relatively high concentrations in soil 0-40 cm deep, but only at low concentrations in soil 40-80 cm deep. The surface soil concentrations appear to have been strongly affected by crude recycling activities, and former open burning and dismantling sites were the main point sources. The areas surrounding the open burning sites and dismantling sites have been contaminated not only by the dumping of waste residues but also by fly ash deposition, even though the agricultural soils are far from the point pollution sources. Some BPA in the soils is likely to be the reductive debromination product of TBBPA because the long rainy season promotes TBBPA transformation and because BPA can persist for a long time. Incubation experiments confirmed that TBBPA could be transformed into BPA and that BPA could accumulate in waterlogged paddy soils, and this may be why BPA concentrations were higher than TBBPA concentrations in the Longtang area.